Certain foam products for topical application of therapeutical agents and cosmetics have been prepared as oil-in-water emulsions. Foams and, in particular, foam compositions having a high oil content are complicated systems that do not form under all circumstances. Slight shifts in foam composition, such as the addition of an active ingredient, may destabilize the foam. It is known in the art that hydrophobic solvents are difficult to formulate into a foam-producing product. Addition of conventional hydrophobic solvents interferes with the foam forming ability of the surfactant, and thus, in the few foam products containing high-oil concentrations that have been reported, high surfactant concentrations are used, which may cause undesirable irritancy on one hand, and costly raw material usage on the other hand are used.
Oleaginous formulations for the preparation of cosmetic and therapeutic compositions are known in the art.
U.S. Pat. No. 6,620,773 relates to a foaming oil composition, which includes a surfactant mixture and an oil component, the surfactant mixture containing an anionic or zwitterionic surfactant, a nonionic surfactant and at least one ethoxylated alkyl phosphate ester component. The surfactant mixture ranges from about 15% to about 50% of the total composition, and that of the oil component ranges from about 50% to about 85%.
U.S. Pat. Nos. 5,700,396 and 5,589,515 disclose a cosmetic emulsion composition containing 0.1 to 99 wt % oily component (balance aqueous component). The oily component includes 85% or more weight % of cis Δ9-octadecanoic acid or derivatives thereof, which serves as a surfactant in the formulation.
U.S. Pat. No. 6,524,594 describes a gelled oil composition containing an emulsifier, a gelling agent, an oil, and a surfactant which, when applied to the skin in the presence of water, produces a significant amount of foam. The surfactant is used in an amount from about 10% to about 20%, and more preferably, from about 15% to about 20%.
U.S. Pat. No. 6,121,210 discloses foamable, silicone oil compositions and methods of lubricating surfaces with such compositions. The compositions are oil-in-water emulsions comprising silicone oil-in-water emulsion, a liquid propellant and a foam builder comprising a solid, non-ionic lipophilic surfactant having an HLB value of about 3 to about 8. Foam stabiliziers including long claim fatty alcohols are included. A propellant is included to create a foamable composition.
In general, the foamable compositions of the art are based on oil-in-water emulsions. Furthermore, they often include a high content level of surfactants and foaming agents required to form acceptable foams which are stable and possess low specific gravity. Such surfactants, and particularly ionic surfactants, such as anionic surfactants (e.g. sodium lauryl sulfate (SDS)), may have adverse affects on certain patients, including concentration-dependent skin irritation.
There remains an unmet need for improved, stable and non-irritating oleaginous foam formulations, intended for dermal and mucosal delivery of pharmaceutical and cosmetic, with unique therapeutic and cosmetic properties.